This Volvo 1.6 D diesel arrived at AutoChip after failing its roadworthiness inspection because of excessive smoke. Black smoke appeared as the engine was revved. When the accelerator was held down for longer, lighter grey smoke with the smell of unburned fuel became noticeable. The engine also ran unevenly and vibrated strongly.

What the ECU inspection showed

The EDC16C34 engine control unit was removed and read on the bench. Comparing the installed software with an original file showed that the previous calibration had reduced engine power and changed the engine control parameters. The technician concluded that the calibration had been aimed at reducing visible smoke.

The shop carried out diagnostics and reviewed data logs, revised the ECU software and made a modest increase in power. Smoke was noticeably lower after the software changes than it had been before the work. This alone does not confirm that the mechanical cause of the smoke has been fixed or that the vehicle passed its roadworthiness inspection.

Further checks required

The video shows that the turbocharger is not in the best condition and has signs of an oil leak. The technician recommended removing it for inspection; injector operation also needs further assessment. The shop planned to review the data logs and test results, then give the owner information on which engine components should be checked first. The ECU calibration was revised, but the video does not confirm that any required mechanical repairs were completed.